scroll-snap-stop

scroll-snap-stop: normal;

scroll-snap-stop: always;

<section class="default-example" id="default-example">
  <p class="explanation">
    The effect of this property can be noticed on devices with a touchpad. Try
    to scroll through all items with a single swing. Value
    <b class="keyword">'normal'</b> should pass through all pages, while
    <b class="keyword">'always'</b> will stop at the second page.
  </p>
  <div class="snap-container">
    <div>1</div>
    <div id="example-element">2</div>
    <div>3</div>
  </div>
  <div class="info">Scroll »</div>
</section>

.default-example {
  flex-direction: column;
}

.explanation {
  margin-top: 0;
}

.keyword {
  color: darkorange;
}

.default-example .info {
  width: 100%;
  padding: 0.5em 0;
  font-size: 90%;
}

.snap-container {
  text-align: left;
  width: 250px;
  height: 250px;
  overflow-x: scroll;
  display: flex;
  box-sizing: border-box;
  border: 1px solid black;
  scroll-snap-type: x mandatory;
}

.snap-container > div {
  flex: 0 0 250px;
  width: 250px;
  background-color: rebeccapurple;
  color: white;
  font-size: 30px;
  display: flex;
  align-items: center;
  justify-content: center;
  scroll-snap-align: start;
}

.snap-container > div:nth-child(even) {
  background-color: white;
  color: rebeccapurple;
}

/* Keyword values */
scroll-snap-stop: normal;
scroll-snap-stop: always;

/* Global values */
scroll-snap-stop: inherit;
scroll-snap-stop: initial;
scroll-snap-stop: revert;
scroll-snap-stop: revert-layer;
scroll-snap-stop: unset;

<p>scroll-snap-stop: always (X Mandatory)</p>
<div class="x mandatory-scroll-snapping always-stop">
  <div>1</div>
  <div>2</div>
  <div>3</div>
  <div>4</div>
  <div>5</div>
</div>

<p>scroll-snap-stop: always (X Mandatory) on odd child elements</p>
<div class="x mandatory-scroll-snapping always-stop-odd">
  <div>1</div>
  <div>2</div>
  <div>3</div>
  <div>4</div>
  <div>5</div>
</div>

<p>scroll-snap-stop: always (X Mandatory) on even child elements</p>
<div class="x mandatory-scroll-snapping always-stop-even">
  <div>1</div>
  <div>2</div>
  <div>3</div>
  <div>4</div>
  <div>5</div>
</div>

<p>scroll-snap-stop: normal (X Mandatory)</p>
<div class="x mandatory-scroll-snapping normal-stop">
  <div>1</div>
  <div>2</div>
  <div>3</div>
  <div>4</div>
  <div>5</div>
</div>

<p>scroll-snap-stop: always (Y Mandatory)</p>
<div class="y mandatory-scroll-snapping always-stop">
  <div>1</div>
  <div>2</div>
  <div>3</div>
  <div>4</div>
  <div>5</div>
</div>

<p>scroll-snap-stop: normal (Y Mandatory)</p>
<div class="y mandatory-scroll-snapping normal-stop">
  <div>1</div>
  <div>2</div>
  <div>3</div>
  <div>4</div>
  <div>5</div>
</div>

/* setup */
body {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-flow: column nowrap;
  font-family: monospace;
  text-align: center;
}

div[class] {
  font-size: 3rem;
  display: flex;
  overflow: auto;
  flex: none;
}

.x {
  width: 50%;
  min-width: 15rem;
  height: 6rem;
  flex-flow: row nowrap;
}

.y {
  width: 30%;
  min-width: 12rem;
  height: 12rem;
  flex-flow: column nowrap;
}

div > div {
  flex: none;
  outline: 1px solid #333333;
}

.x > div {
  width: 90%;
  height: 100%;
}

.y > div {
  width: 100%;
  height: 80%;
}

/* coloration */
div > div:nth-child(even) {
  background-color: #87ea87;
}

div > div:nth-child(odd) {
  background-color: #87ccea;
}

/* setting up mandatory scroll-snap on parent */
.x.mandatory-scroll-snapping {
  scroll-snap-type: x mandatory;
}

.y.mandatory-scroll-snapping {
  scroll-snap-type: y mandatory;
}

/* defining scroll-snap alignment on children */
div > div {
  scroll-snap-align: center;
}

/* defining scroll-snap stop on children */
.always-stop > div {
  scroll-snap-stop: always;
}

.always-stop-odd > div:nth-of-type(odd) {
  scroll-snap-stop: always;
}

.always-stop-even > div:nth-of-type(even) {
  scroll-snap-stop: always;
}

.normal-stop > div {
  scroll-snap-stop: normal;
}